137 lines
3.5 KiB
C
137 lines
3.5 KiB
C
#include "parser.h"
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#include "object.h"
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#include "tokens.h"
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#include <assert.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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static void expect(Tokens tokens, enum TokenType token_type);
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static struct Object *expr(Tokens tokens);
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static struct Object *parens(Tokens tokens);
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static struct Object *parens_part(Tokens tokens);
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void expect(const Tokens tokens, const enum TokenType token_type)
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{
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assert(Tokens_expect(tokens, token_type));
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}
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struct Object *parse(const Tokens tokens)
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{
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return expr(tokens);
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}
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struct Object *expr(const Tokens tokens)
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{
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assert(Tokens_top(tokens));
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switch (Tokens_top(tokens)->type) {
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case TOKEN_ROUND_OPEN:
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case TOKEN_SQUARE_OPEN:
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case TOKEN_CURLY_OPEN:
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return parens(tokens);
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case TOKEN_QUOTE:
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Tokens_pop(tokens);
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return \
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Object_build_list(2, Object_new_symbol("quote"), expr(tokens));
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case TOKEN_QUASI_QUOTE:
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Tokens_pop(tokens);
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return \
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Object_build_list(2, Object_new_symbol("quasiquote"), expr(tokens));
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case TOKEN_QUASI_UNQUOTE:
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Tokens_pop(tokens);
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return \
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Object_build_list(2, Object_new_symbol("unquote"), expr(tokens));
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case TOKEN_TAG:
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{
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struct Object *object = NULL;
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const char *const val = Tokens_top(tokens)->val;
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assert(val);
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if (strcmp(val, "f") == 0 || strcmp(val, "false") == 0) {
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object = Object_new_boolean(false);
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} else if (strcmp(val, "t") == 0 || strcmp(val, "true") == 0) {
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object = Object_new_boolean(true);
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} else {
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assert(0);
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}
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Tokens_pop(tokens);
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return object;
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}
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case TOKEN_IDENT:
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{
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struct Object *const object = Object_new_symbol(Tokens_top(tokens)->val);
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Tokens_pop(tokens);
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return object;
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}
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case TOKEN_NUM:
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{
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struct Object *const object =
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Object_new_number(atoll(Tokens_top(tokens)->val));
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Tokens_pop(tokens);
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return object;
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}
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case TOKEN_STRING:
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{
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struct Object *const object =
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Object_new_string(Tokens_top(tokens)->val);
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Tokens_pop(tokens);
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return object;
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}
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default:
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abort();
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return NULL;
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}
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}
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struct Object *parens(const Tokens tokens)
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{
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assert(Tokens_top(tokens));
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struct Object *object = NULL;
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if (Tokens_top(tokens)->type == TOKEN_ROUND_OPEN) {
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expect(tokens, TOKEN_ROUND_OPEN);
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object = parens_part(tokens);
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expect(tokens, TOKEN_ROUND_CLOSE);
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} else if (Tokens_top(tokens)->type == TOKEN_SQUARE_OPEN) {
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expect(tokens, TOKEN_SQUARE_OPEN);
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object = parens_part(tokens);
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expect(tokens, TOKEN_SQUARE_CLOSE);
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} else {
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expect(tokens, TOKEN_CURLY_OPEN);
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object = parens_part(tokens);
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expect(tokens, TOKEN_CURLY_CLOSE);
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}
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return object;
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}
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struct Object *parens_part(const Tokens tokens)
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{
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assert(Tokens_top(tokens));
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if (Tokens_top(tokens)->type == TOKEN_ROUND_CLOSE ||
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Tokens_top(tokens)->type == TOKEN_SQUARE_CLOSE ||
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Tokens_top(tokens)->type == TOKEN_CURLY_CLOSE)
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{
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return NULL;
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}
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struct Object *const a = expr(tokens);
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assert(Tokens_top(tokens));
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struct Object *b = NULL;
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if (Tokens_top(tokens)->type != TOKEN_ROUND_CLOSE &&
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Tokens_top(tokens)->type != TOKEN_SQUARE_CLOSE &&
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Tokens_top(tokens)->type != TOKEN_CURLY_CLOSE)
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{
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b = parens_part(tokens);
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}
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struct Object *object = Object_new_pair(a, b);
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return object;
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}
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